Atomizing structure



*mw w RG Y M6@ mail mm www j W5 ,m m. PH ma m M m Nw 3 m u\\\\ a n V ivf y A @RL I M a f mm R m J m mm m w o@ m m m. Nlm I M s u d A w m M F Patented Oct. 11 1949 ATOMIZING STRUCTURE Alexander S. King, Jr., Prospect Park, Pa., as-

signor to Westinghouse Electrlc Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application May 29, 1945, serial No. v596,508

s claims. (ci. 299-120) 1 This invention relates to liquid fuel atomizing nozzles, more particularly to nozzles of that type for use in gas turbine power plants, and has for ian object to provide an improved device of this character.

Another object of the invention is to provide aliquid lfuel nozzle capable of atomizlng the fuel at a much lower pressure than is possible with previously known nozzles.

A further object of th'e invention is to provide a liquid fuel nozzle capable of atomizing the fuel at a much lower rate of flow than is possible with previously known nozzles.

While nozzles constructed in accord-ance with the present invention will be found -useful in many situations and types of apparatus, they are particularly useful in combustion apparatus for gas turbine power plants.

A typical power plant of the type referred to is disclosed in the copending application of Stewart Way, Serial No. 482,533, led April 10, 1943, now Patent No. 2,405,723 wherein there is described a gas turbine power plant for propulsion of aircraft, and includes an air compressor, air heating apparatus, a turbine, and a propulsion jet nozzle all housed within a streamlined tubular casing. A plant of this character is particularly suitable forpropelling aircraft lat high speeds and operates generally as follows: Air enters the forward end of the tubular casing and is compressed in the compressor, the compressed airis then heated in the heating apparatus by combustion of fuel, supported bythe compressed air. The resulting motive fluid, comprising the products of combustion and the excess compressed air, drives the .turbine and is then discharged through the propulsion nozzle as a jet, the reaction of which serves to propel the aircraft. The turbine extracts at least suilcient power from the motive fluid to drive the compressor and auxiliaries. The fuel is supplied `to the lair heating apparatus, under the control of a throttle valve,

bodylng the present invention, portions of the apparatus being broken away for the sake of clearness;

Fig. 2 is an enlarged longitudinal sectional view of a liquid fuel atomizing nozzle used inthe apparatus shown in Fig. 1, .and constructed in accordance with the invention;

Fig. 3 is van exploded sectional view of the structure shown in Fig. 2; and,

Fig. 4 is a view taken along the line IV-IV of Fig. 3 looking in the direction indicated by the arrows.

The power plant shown in Fig. 1 comprises in general an outer casing structure I0, open from end to end, and having a central core structure Il providing an annular flow passage I2, which extends fore and aft with respect to the aircraft in which it is mounted. The central core structure I I is supported by the casing structure along its longitudinal axis and includes a hollow fairing cone I4, defining with the forward or left end of the casing I0, as viewed in Fig. 1, the inlet portion of the flow passage I2. The fairing cone houses a fuel pump, generally indicated I5, and other auxiliary Iapparatus for example, fuel controls lia, and is supported from the casing by hollow compressorl guide vanes I6. The core structure also includes the rotor I I of an axial ilow compressor I8, the fixed blades of which are carried by the casing I0, the rotor I 9 of a turbine 2I, and a conical tailpiece 22 4which defines, with the rear end of the casing structure, a propulsion nozzle 23. The intermediate portion of the core structure between the compressor and the turbine comprises an inner wall structure 24, which houses a shaft 25 connecting the tur-bine rotor I9 and compressor rotor l1, and denes with the casing I Il an annular combustion chamber 26. The shaft 25 is journaled in suitable bearings 25a, carried by the outer casing.

The combustion chamber 2B is provided with a suitable burner or burners, such as shown in the copending application of Way et al., Serial No. 511,468, filed November 23, 1943, for heating the air compressed by the compressor. In the embodiment shown herein, a perforated, tapered, annular burner tube 21 is mounted in the annular combustion chamber 26 with its large open end 28 directed downstream. Fuel under pressure is supplied to the burner tube from a manifold pipe 29 connected to a fuel supply and is fed from the manifold through branch pipes 3| to atomizing nozzles 32 extending into the burner tube through the small closed end 33 thereof. Suitable means, including spark plugs 34, extending into the 3 burner tube, are provided for ignitingI the air-fuel mixture.

The power plant operates substantially as follows: Air enters the casing I at the inlet of the iiow passage I2, is compressed by the compressor, and flows into a diffuser or divergent portion 85 of the flow passage, which eects a further com pression 4of the air. The compressed air then passes through the openings provided in thewalls of the burner tube 21. The compressed air mixes with the fuel atomized in the tube by the nozzles 32. The air and fuel mixture is ignited by the spark plugs and burns steadily thereafter. The hot gases or motive fluid comprising the products of combustion and the excess air heated by the combustion, on leaving the burner tube 21 are directed by fixed guide vanes or nozzles 38, of the turbine 2i, into the passage of the turbine rotorv I9. The turbine extracts at least suiilcient energy from the motive fluid to drive the compressor I8, pump I5, fuel controls Ia, and other auxiliary apparatus that may be housed in the fairing cone I4. The spent gases leaving the turbine are discharged through the propulsion nozzle 23 at a high velocity, so that the remaining energy in the motive fluid is available to propel the aircraft. The tailpiece 22 is preferably axially movable with respect to the casing structure so that the back pressure on the turbine and the jet effect produced by the nozzle may be varied.

The present invention is particularly concerned with the construction and operation of the nozzles 32, and inasmuch as they preferably are similar, only one will be hereinafter described.

Referring now particularly to Figs. 2, 3 and 4,- the nozzle 32 is comprised by a shell 68 having a cylindrical bore 5I therein, closed at the front or forward end by the wall 52 which, preferably, has a convex outer surface 53 and a conical inner surface 54, the wall 52 being provided with an emission opening 56 at the apex of the conical inner wall 54, and concentric with respect to the longitudinal axis of the cylindrical bore 5I.

The cylindrical bore 5I is internally threaded as at 51, for a portion of its length adjacent the rearward or open end thereof for reception of a core assembly, indicated in its entirety by the reference character 58. Core member 68 has an external flange 6I provided with threads 62 for engagement with the internal threads 61 of the nozzle shell 50, the rearward portion of the core member being provided with a bore 63 and the central and forward portion thereof having a bore 64 of greater diameter than of the bore 63.

A swirl member 66, having a cylindrical portion 61 adapted to be frictionally received within the bore 64 of the core member 60, is provided with a head portion 68, having a shoulder 68 adapted to abut the mating shoulder 1I at the end of the core member 68, to limit the inward position of the swirl member with respect to the enlarged cylindrical bore 64 of the core member. The forward end of the swirl member 66 is provided with a recess having a conical bottom wall 12 and a circular side wall 13 providing a swirl chamber 13a. The end face 14 of the swirl mem-l ber 66 is preferably conical and formed at an angle corresponding to the angle of the' conical surface 54 of the shell end wall 52. This end surface 14 is provided with a pluralityl of passages 16, extending from periphery of the swirl member head sa to the anmuar wall 1s of the swn-1 chamber 13a, for a purpose to be hereinafter described. Preferably, these passages or channels 16 are disposed in a substantially tangential relation to the annular wall-13 of the swirl chaxnbeil The shoulder 68 on the swirl member 86 serves to position the rearward end of the swirl member in spaced relation to the inner end of thesmaller bore 63 of the core member 60, thereby providing a chamber 18 to which liquid fuel under pressure may be supplied through the bore 63. One or more openings 18 are provided in the wall of the chamber 18 and serve to conduct fuel from the chamber 18 to the annular space 8| between the core member 60 and the shell 5D, when the former is assembled within the latter, as indicated in Fig. 2.

Positioned between the conical surfaces 54 and 14 of the shell and swirl members, respectively, is an orifice plate 83, having an edge portion 84 of conical form to mate with the conical surfaces 54 and 14 between which it is flxedly clamped. A central portion 85 of the orifice plate extends at right angles to the longitudinal axis of the cylindrical bore 5I and is provided with an opening 86 concentric about said axis of the cylindrical bore 5I. It will be apparent from consideration of Fig. 2, that this orifice member 83 provides chambers at opposite sides thereof with theorifice 86 providing communication therebetween.

The passages 16 (Fig. 4) previously described, serve to admit fuel from the annular space 8I to the interior of the swirl chamber with a swirling action, due to the substantially tangential arrangement of the passages, the fuel passing from the swirl chamber 13a to the secondary chamber 81, at theopposite side of the orifice 83 from the swirl chamber, and thence through the emission orifice 56 to the interior of the burner tube.

Preferably, although not necessarily, the orifice member 83 is made of copper, or some material having similar characteristics, whereby it serves the additional functions of providing a resilient leakproof seat between the shell and the core, and to a certain extent acts as a lock for the core. Obviously, any leakage between the core and the shell Will seriously affect proper functioning of the nozzle as a whole.

It has bcen found desirable to have the orice 86, in the orice member 83, of approximately twice the diameter of the emission opening 56 in the end wall 52 of the shell. As a result of provision of the orifice/plate with the orifice therein of substantially double the diameter of the emission opening 56, atomizing may be obtained as for a pressure as low as 2 lbs. per sq. in, gauge, compared with a minimum heretofore obtainable pressure of 6 lbs. per sq. in. gauge. Furthermore,

this construction permits satisfactory atomization with a flow of as low as 11 lbs. per hour as compared Witha normal minimum satisfactory flow of 18 lbs. per hour. Thus, it will be apparent that applicant has provided a construction providing for satisfactory operation of a liquid fuel atomizing nozzle within a. range oi pressure and flow conditions of considerably lower minimum limits than is possible with constructions heretofore amps? structure disposed in the bore and closing the open end thereof, said core structure having a swirl chamber formed by a recess in its inner end aligned with, and facing, the emission orifice; means for conducting fuel to said swirl chamber and for causing it to swirl therein; and a plate positioned between the swirl chamber and the emission orificefin spaced relation to the latter and provided with: an orifice which is aligned with the emission orice and is vof greater cross sectional area than the latter, said plate being clamped by, and forming a seal between, the core structure and the shell.

2. A liquid fuel atomizing nozzle comprising an outer shell having a cylindrical chamber open at one end and closed at the opposite end by an end wall having an orifice therethrough coaxial with the chamber, an inner core structure positioned in the cylindrical chamber and closing the other end thereof, the inner portion of said core structure being circular in cross-section and of materially lesser diameter than the cylindrical chamber whereby there is provided between the core structure and the shell an annular space, the end face of said core structure which is opposed to the oriced end wall of the shell having a cir- `cular recess formed therein providing a swirl chamber coaxial with the cylindrical chamber and having its side wall separating it from the annular space between the core structure and the shell; means for admitting fuel under pressure to the annular-space; means for directing the fuel from the annular space to the swirl chamber for swirling movement therein; and a relatively thin wall structure positioned between the swirl chamber and the oriced end wall of the shell and spaced from the latter, said thin wall structure having an orifice therethrough coaxial with the shell end wall orifice and of materially greater cross-sectional area than the latter, and said thin wall structure being clamped by, and providing a seal between, the core structure and the shell.

3. A liquid fuel atomizing nozzle comprising an outer shell providing a cylindrical bore open at 6 the rear and closed at the opposite end by a front wall having an orifice therethrough coaxial with the bore, the inner surface of said front wall being concaved; a core structure positioned in said bore and closing the other end thereof, the

forward portion of said core structure having its outer circumferential surface spaced from the inner circumferential surface of the bore a materialdistance to provide therebetween an annular now-path for fuel, and the front end of said core structure having a circular recess therein providing a swirl chamber;I a diaphragm clamped between the inner concave surface of the shell front wall and the front end of the core structure, said diaphragmhaving a central portion normal to the axis ofv the bore and separating said swirl chamber recess from a space dened by the front side of said diaphragm central portion and the concaved inner surface of the shell front wall, said diaphragm having an orice therethrough lcoaxial with the bore; means for conducting fuel to the annular space between the core structure and the shell side wall; and means for directing fuel from said annular space to the swirl chamber for swirling motion therein.

ALEXANDER S. KING, Jn.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

